Electronic towel dispensers are well know in the art, including dispensers that automatically dispense a metered length of towel material upon sensing the presence of a user. This type of dispenser has become known in the art as a “hands-free” dispenser in that it is not necessary for the user to manually actuate or otherwise handle the dispenser to initiate a dispense cycle. The control systems and mechanical aspects of conventional hands-free dispensers are wide and varied.
For example, U.S. Pat. No. 5,772,291 describes an electronic hands-free towel dispenser powered by an array of photovoltaic cells. The dispenser utilizes a photo sensor to detect the presence of a user through the front cover of the housing; the photo sensor and associated control circuitry activate a motor to dispense a predetermined length of towel upon detecting the user. The photo sensor reacts to changes in a room's ambient light intensity, and when a person places an obtrusion, such as their hand, within a predetermined distance (detection range) of the front of the dispenser, the amount of ambient light reaching the photo sensor is decreased sufficiently to cause the photo sensor and control circuitry to register a “detect” and initiate a dispense cycle.
U.S. Pat. No. 6,419,136 describes an electronic dispenser for dispensing individual towel segments from a continuous roll of paper having spaced perforation or tear lines. By using perforated web material, the individual sheets can be separated from the roll by a user grasping a length of the material that extends out of the housing and tearing the sheet along a perforation line. A cutting mechanism is not necessary and energy is conserved because the motor only rotates a feed roller. The control circuitry includes a proximity sensor coupled with a microprocessor to activate the drive motor when the user's hand is detected. The proximity sensor is disposed to “look” through the front cover of the dispenser housing.
U.S. Pat. No. 6,412,655 describes an AC powered towel dispenser that utilizes a capacitive sensor on the front of the dispenser housing. The sensor includes electrodes disposed behind a sensor field in the cover that may cover the entire width of the housing. The electrodes establish a dielectric having a defined capacitance in the idle state. If there is a change in the dielectric caused by a user placing their hand in front of the dispenser housing, a change in the capacitance results and triggers a dispensing sequence.
U.S. Pat. No. 5,452,832 describes an automatic paper towel dispenser wherein a photocell detector actuates an on-off switch for supplying power to a drive motor for a specified time period to dispense a length of paper towel. The photocell is disposed on the side of the dispenser housing.
The art is thus constantly seeking ways to improve upon conventional hands-free towel dispensers. The present invention relates to such an improvement.